A protester has been found dead in Bahrain after overnight clashes with police, stirring more fury on the eve of a Formula One Grand Prix that anti-government activists have vowed to mark with "days of rage".

Bahrain's government has spent $40 million to host the global sporting event, hoping to demonstrate that normal life has returned to the Gulf island kingdom after it cracked down on Arab Spring demonstrations last year.

But vivid televised images of streets ablaze - as masked youths hurl petrol bombs and police fire teargas and birdshot - have cast a shadow over the event.

The protesters, mostly from the majority Shiite Muslim community, blame the Sunni ruling elite for shutting them out of opportunities, jobs and housing.

They have made it clear they will use the international attention the motor race has focused on Bahrain to air their grievances.

The death is expected to intensify the wave of protests against the race.

The government are using the Formula One race to serve their PR campaign. It's not turning out the way they wanted.

Bahrain activist Nabeel Rajab

Opposition party Wefaq has published a photograph of a body splayed on a corrugated iron rooftop in the village of Shakhura, near the capital Manama.

It identified him as Salah Abbas Habib, 37.

Wefaq says it is unclear what caused his death, but says he was part of a group of protesters who were beaten by police during clashes late on Friday night.

"We haven't got the body because the official investigators have surrounded the area but we understand he was beaten severely," Wefaq official Sayed Hadi al-Mousawi said.

"His colleagues with him last night were beaten with batons and the butts of rifles used to shoot tear gas and bird shot."

Bahrain's Interior Ministry says it is launching an investigation.

A funeral march for Mr Habib will take place on Sunday (local time), setting the stage for riots during the big race itself.